1. Field of the Invention
The present invention relates to a recording media cartridge such as a magnetic tape cartridge or cassette typified by a digital video cartridge (DVC), and more particularly to a recording media cartridge for reducing a burden on the environment.
More specifically, the present invention relates to a fastening structure by which a case body (cassette case) is fastened by coupling an upper half of the case body with a lower half in a recording media cartridge such as a magnetic tape cassette or cartridge. More particularly, the present invention relates to a fastening structure of a case body in a recording media cartridge which enables easy separation of an upper half from a lower half when various components constituting the recording media cartridge scraped after use are disassembled and sorted for every kind of material to be recycled as new material.
2. Description of the Related Art
A magnetic tape cartridge or cassette (hereinafter typically referred to as a magnetic tape cartridge) of a so-called two-reel type in which a pair of takeup hubs (tape reels) around which a magnetic tape as a recording medium is wound is accommodated rotatably in a case body (cartridge body, case body or cassette case) formed by an upper half and a lower half, or a magnetic tape cartridge or cassette of a so-called one-reel type in which a single tape reel around which a magnetic tape is wound is accommodated rotatably in the case body mentioned above is conventionally known as a recording/reproducing tape cartridge or cassette used in a video tape recorder or a video camera for personal use or office use or a large capacity recording medium for data backup in an external storage apparatus such as a computer. A large capacity recording medium such as a magnetic or magneto-optical disc cartridge which uses a magnetic or magneto-optical disc for the recording medium is also well known.
Recording media cartridges such as a magnetic or magneto-optical disk cartridge, a magnetic tape cartridge and a magnetic tape cassette referred to above are used for data storage in a computer etc. to retain important information recorded therein, so that various protection mechanisms are added thereto for preventing a damage of a magnetic or magneto-optical disk, or a jamming of a magnetic tape or inadvertent draw-out thereof.
A magnetic tape cartridge of two-reel type will now be described in detail.
FIG. 24 is an exploded perspective view showing a structure of the above-mentioned DVC (digital video cartridge) which is an exemplary magnetic tape cartridge. As shown in FIG. 24, the magnetic tape cartridge for use as the DVC (hereinafter simply referred to as cartridge) is adapted to perform recording and reproduction while a magnetic tape 426 wound around a pair of tape reels 424 is held movably in a case body 410. The case body 410 is constituted by assembling an upper half 420 and a lower half 422 each having a bottom plate and a peripheral wall in a capped manner and fastening with screws (five screws 412 in the illustrated case). A pair of tape reels 424 on the supply side and take-up side are accommodated rotatably in the case body 410 in the state in which the magnetic tape 426 is wound around the tape reels 424. A lid (front cover) 430 which can be opened or closed freely is also mounted on the upper half 420 to cover a front surface of the case body 410 and to protect the front portion from dust.
A plurality of regulating ribs are erected on the bottom plate 422a of the lower half 422 in such a way that they comply with the outer peripheries of the tape reels 424, 424 and by these ribs, the tape reels 424, 424 are prevented from being displaced in a direction parallel to their planes. An opening is made in the bottom plate of the upper half 420 such that the user can confirm the amount by which the magnetic tape 426 has been would onto the tape reels 424, 424 and a transparent window (inspection window) 420a is provided to cover the opening.
Provided on the inner surface (the underside in the drawing) are a pair of reel urging leaf springs (reel holding springs) 438, 438 which correspond to the respective tape reels 424, 424. The reel holding springs 438, 438 are each cantilevered to the inner surface of the upper half 420 by means of ultrasonic welding, thermal welding or the like so that the corresponding tape reels 424, 424 are urged toward the lower half 422.
Mounted at the front face of the upper half 420 (its left side in the drawing) is a lid (front cover) 430 that covers and protects the magnetic tape 426 when the cartridge is not in service. As will be described later, the lid 430 comprises of three members, an outer lid 432, an upper lid 433, and an inner lid 434, and each of which is mounted in such a way that an opening portion 428 in the magnetic tape cartridge can be opened or closed as required.
Two tape guides 446, 446 are provided on two extensions 440, 440 on opposite sides of the opening portion 428 made at the front end of the lower half 422 (closer to the viewer of the drawing). The magnetic tape 426 being delivered from one tape reel 424 and taken up by the other tape reel 424 is guided by each tape guide 446 so that it passes by a predetermined position in the opening portion 428.
The lower half 422 has a tape reel locking member (hereunder simply referred to as a reel locking member) 436 mounted at its rear end (farther away from the viewer of the drawing). The reel locking member 436 has a tape reel lock (engaging and fastening) arm 436a and a slider body 436b which is slidably pinched by a pair of guide ribs erected on the bottom plate 422a of the lower half 422. The reel locking member 436 is urged by a compressive coil spring 442 so that the tape reel lock arm 436a is engaged with each of engagement wheels 424a, 424a formed on the outer peripheries of the lower flanges of the tape reels 424, 424, thereby preventing accidental rotation of the tape reels 424, 424. As a result, troubles with the magnetic tape 426 such as failure to be wound up tightly enough can be prevented.
While the outer lid 432, the upper lid 433 and the inner lid 434 of the lid 430 are mounted on the upper half 420 as described above, the outer lid 432 has a flat plate portion and two side plates, with locking pins 448 projecting inside of the side plates. To sidewall portion 422c that are parts of the peripheral wall of the lower half 422, lid locking members 444, 444 are mounted pivotally such that they lock the locking pins 448 on the outer lid 432 when it is in a closed state. A lid locking spring 450 is similarly mounted on the lower half 422 to urge the lid locking members 444, 444 in the direction of locking the aforementioned locking pins 448.
An anti-erasure plug 452 is mounted on the lower half 422 to circumvent erroneous erasing of the data recorded on the magnetic tape 426. The anti-erasure plug 452 has a pawl projecting on one of its two lateral sides (farther away from the viewer of the drawing) so that when the plug is mounted in the lower half 422, the pawl will become exposed to the outside through the opening made in the peripheral wall of the upper half 420.
By manipulating the pawl from the outside, the user can move the anti-erasure plug 452 along the guide ribs erected on the bottom plate 422a of the lower half 422. The moving bottom of this anti-erasure plug 452 closes or opens the detection hole in the bottom plate of the lower half 422 and an apparatus such as a recorder reads the state of this detection hole to determine whether new data can be written to the magnetic tape 426.
The lower half 422 has a rectangular bottom plate 422a. A pair of tape reels 424, 424 around which the magnetic tape 426 is wound are rotatably supported on this bottom plate 422a. There are provided reel spindle insertion holes 422b for, when the cartridge is loaded in a recording/reproducing apparatus, inserting reel spindles (not shown) into the above-described tape reels 424, 424 from the recording/reproducing apparatus for rotating and driving the tape reels 424, 424.
Furthermore, the above-mentioned bottom plate 422a has two extensions 440, 440 extending frontward from the both ends thereof, and on which two cylindrical tape guides 446, 446 are erected at right angle with the bottom plate 422a for guiding the magnetic tape 426 tensioned between the aforementioned pair of tape reels 424, 424 and passing through a predetermined rout into the front surface of the cassette case. The space between the two extensions 440 where the bottom plate 422a of the lower half 422 is cut out, forming the opening portion 428 in the above-mentioned cassette case.
Parts including the mentioned upper and lower halves 420 and 422, the outer lid 432, the upper lid 433 and the inner lid 434 of the lid 430, and the upper and lower flanges of the tape reels 424, 424 are respectively formed by injection molding. And other parts that are formed by injection molding are employed to the cartridge as appropriate.
By the way, recently, as a concern to the environmental issue has been increased, the attention is paid increasingly to the adverse effect on the environment of the increase of various kinds of waste materials such as plastics or composite materials. It becomes important to reduce the burden on the environment, i.e., to reduce the waste materials, or to produce no factors causing air, water or soil pollution even if wasted so that the environmental conservation cannot be hindered. For this reason, industrial products must have a structure enabling incorporation in a recycling system, and a structure is desired which may be suited for the recycling system for the whole society. In view of this, it becomes also necessary to manufacture a recording media cartridge such as a magnetic tape cartridge taking into consideration the structure or material therefor.
However, in the magnetic tape cartridge as mentioned above, the upper half and the lower half constituting the case body are conventionally coupled with each other by metal screws, and a magnetic tape made of a different material than that of the case body is accommodated in the case body in a state in which the tape is wound around a reel also made of a different material than that of the case body.
As mentioned above, components of the conventional magnetic tape cartridge or other recording media cartridges are made of various kinds of materials such as synthetic resin, metal, composite material of metal and synthetic resin and other material. Accordingly, it is difficult to dismount (sort) the materials for every kind of material. Also, even if the used recording media cartridge may be dismounted, it is difficult to separate and sort the materials for every kind of the material and to recycle the material. This would be a cause of generating a large amount of waste resin material. The waste resin material causes the environmental burden.
For instance, in the magnetic tape cartridge shown in FIG. 24, the case body 410 is constituted by fastening the upper half 420 and the lower half 422 by five metal screws 412. Accordingly, upon disassembling, troublesome work such as removal of the screws is required. Labor and cost are needed therefor. This is one of causes to prevent the separation of the materials for every kind of material for sorting and collecting, and recycling.
In other words, in the prior art magnetic tape cartridge as mentioned above, the case body for accommodating a pair of tape reels around which a long magnetic tape is wound is usually tightly fastened with five self-tapping screws so as to prevent loosening, which makes it difficult to disassemble the cassette case. In particular, a rusty screw often cannot be removed because the driver grooves in the head of the screw are broken. Even if the screw can be removed, the thus removed screw is likely to be lost and there is a high possibility that the screw may be lost in various components sorted. Therefore, in order to recycle such plastic components for reuse, metal pieces must be sorted again.